Angle nut runner with integral torque transducer means of obtaining value of delivered torque

ABSTRACT

A nut running tool having a rotary air driven vane motor for transmitting torque to a nut or the like to be tightened, and having reaction torque responsive transducer means integrated with the tool and confined within its housing. The transducer is connected by means of an electrical cable running through the handle of the tool to an outlet plug adapted for connection with an external strain gage instrument. The latter is adapted to provide a visible reading of the value of torque that the tool applies to the work.

1111 1191 1111 3,858,44 Wallace 1 1 Jan. 7, 1975 [54] ANGLE NUT RUNNER WITH INTEGRAL 3,596,718 8/1971 Fish et a1. 173/12 TORQUE TRANSDUCER MEANS 01 3,613,853 /1971 Linthicum et a1. 173/12 X 3,710,874 l/l973 Seccombe et al 173/12 OBTAINING VALUE OF DELlVERED TORQUE I r Primary Examiner-Charles A. Ruehl [75] Inventor: fililyliam K. Wallace, Barneveld, Attorney, Agent, or Firm stephen L Rudy [73] Assignee: Chicago Pneumatic Tool Company,

New York, NY. [57] ABSTRACT 22 Ffled; 9 1973 A nut running tool having a rotary air driven vane Y motor for transmitting torque to a nut or the like to be pp N94 331,105 tightened, and having reaction torque responsive transducer means integrated with the tool and con- 52 us. c1. 73/139, 73/136 R, 173/12' fined within its housihg- The transducer is Connected 51 1111.01 B2511 23/14 y means of an electrical cable running through the 58 Field 01 Search 73/136 R, 139,88 F; handle of the tool to an Outlet P adapted for 173 2 nection with an external strain gage instrument. The latter is adapted to provide a visible reading of the 5 References Cited value of torque that the tool applies to the work.

UNITED STATES PATENTS 6 Claims, 5 Drawing Figures 3,385,136 5/1968 Berry et all 73/136 R X ,l' 1 a 62 46 I 14 i 1,- I I1 I 56 L 'k\ 1L- B a i d 15 1 1 1 AA T A 36 fin 52 55 i 49 4| 22 4743 I7 68 69 6| M I 1 I 73 1 l 2 I i L 2 sh ets-Sheet 2 meme Jan 7, 1975 ANGLE NUT RUNNER WITH INTEGRAL TORQUE TRANSDUCER MEANS OF OBTAINING VALUE OF DELIVERED TORQUE BACKGROUND OF THE INVENTION This invention is concerned with a pneumatically powered nut runner having reaction torque responsive means for ascertaining the value of torque the nut runner applies to the work. I

Tools of this general nature are especially suited for use in assembly operations in the automotive and machine industries, and in other areas wherein the value of the torque that is applied in the tightening of threaded fasteners must be known and controlled to meet high standards of safety, quality, durability and the like.

A tool for this general purpose is known from US. Pat. No. 3,596,718, wherein an electro-mechanical transducer housed within the tool is employed for obtaining the value oftorque delivered to the work. In this known device, an element of the transducer mechanism serves as a driving member to transmit torque of the motor to the work, and also reacts to the applied torque to induce an electrical signal in a surrounding induction coil for transmission to an external indicating circuit.

A general objective of the present invention is to incorporate within the tool as an integral part thereof a reaction torque transducer of an improved nature. It is also an object to provide in the tool a reaction torque transducer which is not a member in the torque drive between the motor and the work, and which does not have a surrounding electrical induction mechanism.

The foregoing and other objects and advantages of this invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings wherein an embodiment of the invention is illustrated. It is to be expressly understood, however, that the drawings are for purposes of illustration and descrip tion and they are not to be construed as defining the limits of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. I is a sectional view of an angle head nut running tool embodying the invention;

FIG. 2 is a sectional view, taken on line 22 of FIG. 1 of the rear portion of the tool including the associated hose line;

FIG. 3 is a detail section taken on line 3-3 of FIG. 4 showing the connection of the transducer with the motor housing;

FIG. 4 is a right or rear end view of the transducer shown in FIG. 3; and

FIG. 5 is a detail showing the connection of the electric cable with the transducer.

DESCRIPTION OF PREFERRED EMBODIMENT The invention may best be described and understood with reference to the accompanying drawings wherein there is shown by way of illustration a pneumatically powered angle nut running tool in which the invention is embodied.

The tool includes a general housing comprising a succession of sections coupled in end to end linear rela- 2 tionship. A manually operable throttle valve 10 in a handle section 11 of the housing is employed to feed live supply air through connecting passage means 12 in the housing to drive an air motor 13 located in a motor section I4 of the housing. Rotation of the motor is transmitted through a rotor shaft 15 to an elongated drive shaft 16 and .a double stage of reduction gearing 17 to drive spindle 18 in an angle head front end section I9 of the housing. The spindle is geared in conventional manner at 21 to a drive shank 22 fitted with a work socket 23. The socket is engageable with the work W that is to be torqued, which may be a nut, bolt head or the like. V A spool-form straingage transducer element. 24 (FIGS. 1, 3, 4), has a connection at one end to a double ring gear member 25 of the reduction gearing and is coupled at its opposite end to the motor housing sec tion 14. It is adapted in response to reaction torque transmitted back to it from the work, as when the work is set to a predetermined tightness, to produce a pulse or strain signal in a connected cable 26.The cable connects the transducer with an electrical outlet plug 27 (FIG. 2) fitted in a manifold block28. The latter is coupled to a hose line 29 fitted to the end of the handle. The plug is adapted for connection by means of an external cord line 31 in an electrical circuit of a conventional strain gage indicator instrument, schematically shown at 32 (broken line). The latter responds in conventional manner to a pulse developed by reaction torque of the transducer in the circuit to visibly indicate upon a dial the value of torque applied to the work. Direct current excitation to the transducer is fed in conventional manner from the indicator instrument over the cordline 31 and cable 26. I

The motor 13 is of a conventional air driven vane type. It has arotor 33 operable in a chamber 34 provided by a liner 35. The latter is fixed in usual manner to the housing. Chamber 34 is closed at opposite ends by plates 36 and 37. These carry bearings 38 in which the rotor shaft ends 15 and 39 are supported. Here, the motor is of a stall torque type; it will stall when a predetermined torque resistance is developed by the work.

The transducer 24 is located between the motor and the reduction gearing 17 in a housing section 41. Sec tion 41 has an internal threaded connection 42 at its rear with the motor housing 14, and is coupled at its front end by means of a nut clamp 14 to the angle head section 19.

In the torque transmission drive train to the work, the rotor shaft 15 has a splined driving connection with a bushing 44 fixed internally of a rear end hub 45 of the drive shaft 16. The latter shaft extends coaxially through the transducer element 24 with a slight surrounding clearance 46. A forward end of the drive shaft carries a pinion 47 which is engaged with idler gears 48 mounted in afirst gear cage 49 of the reduction gearing. The idler gears engage a first internal ring gear portion 51 of the double gear member 25; and they are rotatable relative to the latter to cause rotation in a forward direction of the gear cage 49' and a pinion 52 carried by the latter.

Pinion 52 is engaged with a second set of idler gears 53 mounted in a second gear cage 54 of the reduction gearing. The idlers 53 are in turn meshed with a second ring gear portion 55 of the double gear member; and they are rotatable relative to the: latter to drive gear cage 54 in a forward direction. Cage 54 has an internal splined driving connection at 56 with the spindle 18 whereby torque from the motor is finally transmissable through the spindle to the work.

The double ring gear member 25 is not directly connected to, nor directly restrained rotatively by the tools housing; but it is indirectly connected to and restrained rotatively by the tools housing through the transducer element 24. While this indirect connection exerts a restraining torque load upon the double gear member 25 so as to allow the gear cages 49 and 54 to rotate forwardly relative to the double gear member in transmitting torque to the work, it nevertheless does allow a limited degree of strain or torquing of the transducer member in a reverse direction in response to reaction torque returned from the tightened work.

This limited degree of strain or twisting of the transducer is due to the structural nature of the transducer and to the indirect connection of the double gear member 25 through the transducer with the tools housing. In this indirect connection, the double gear member has a rear internal threaded connection with an adapter ring 57 which, in turn, has a rear internal threaded connection with a cylindrical front head 58 of the transducer. The adapter ring is rotatably supported upon a bearing 59 that is fitted upon a rear hub of gear cage 49.

The transducer is of a hollow spool form having front and rear heads 58, 61 joined by an axially extending elongated neck 62 (FIGS. 1, 3 4). The transducer is open through its ends. The neck portion is of reduced diameter relative to the heads and is of thin wall structure. This form of the transducer enables it to twist or strain resiliently to a limited degree under reaction torque load transmitted to it from the work.

The transducer is supported so as to obtain an internal clearance 46 between it and the drive shaft 16. In this arrangement, the transducer will not be frictionally encumbered by the latter. To this end, its front head 58 is supported upon an'internal bearing 63 fitted upon the drive shaft. And its rear head 61 has a peripheral shoulder 64 seated in a collar 65. The collar is seated upon an annular shoulder of the housing 41 and the transducer head 61 is rigidly clamped between the collar and a shoulder 70 of the motor housing by force of the housing connection at 42.

The rear head 61 of the transducer is in an interlocking relationship with the motor housing 14 by means of a pair of keys 66 and by the clamping force resulting from the threaded connection at 42 of the transducer housing 41 with the motor housing 14 (FIGS. 1, 3, 4) whereby the transducer head 61 is restrained against axial and angular movements. The keys are seated upon diametrically opposed surface areas of the transducer head 61 and are retained in such positions by the walls of slots 68 in which they partly extend by pins 67 fitted in holes of the head. At one end, the keys are fitted in part in the complementary slots 68 of the transducer, and opposite portions of the keys are fitted in complementary slots 69 in the end wall of the motor housing.

The transducer has been located directly ahead of the motor because of a desirable advantage such an arrangement provides. This makes it easier to bring or extendthe transducer cable 26 through the tool to a convenient exit location at the rear of the handle without the necessity of using external tubes or connectors, as might otherwise be required.

In this respect, the. cable has a forward terminal 71 threadedly connected in a hole 72 of the transducer head 61 (FIGS. 1, 5). The flexible cable is confined in a surface notch or groove 73 extending in the surface of the motor liner and the adjacent handle housing section 11; and it passes from the notch through a sleeve 74 (FIG. 2) of the handle section. In the sleeve section, the cable is coupled to a cable extension 26a. The latter passes through the sleeve 74, the hose line 29 and the manifold 28 to the electrical outlet plug 27. The latter is mounted in the manifold and the manifold is coupled to the hose line beyond the end of the handle. An air supply line inlet fitting 75, also connected to the manifold, communicates by means ofa feed tube 76 through the hose line and handle with a passage to the throttle valve 10.

In summary of the operation of the tool: after the work socket 23 of the tool is engaged with the work W to be tightened, the throttle valve 10 is manually depressed causing live supply air flow through passages 12 to operate the motor in a work tightening direction. The torque of the motor is transmitted through the drive shaft 16 to the reduction gearing. As a consequence, the idler gears 48 and 53in the first and second stages ofthe reduction gearing rotate relative to the restrained double ring gear 25 to cause rotation of the first and second gear cages 49 and 54. Rotation of the gear cages is-transmitted through the spindle 18 to the work socket to torque' the work.

Torquing of the work continues until the resistance 'of the work exceeds the torque capacity of the motor so as to cause the latter to stall. The reaction torque developing in this action from the torqued work passes through the spindle and idler gears to the double ring gear 25 causing the latter to exert a reaction torque force upon the transducer 24. There is some strain or twisting of the transducer in a reverse direction in response to this action, causing an electrical signal to develop in the cable circuit 26 to the external strain gage indicator instrument 32. The latter, which is of a conventional design, responds to the signal to visually show on a dial face a reading of the value of the torque being applied to the work. While the reaction torque transmitted to the transducer is but a fraction of the actual torque transmitted to the work, it is proportional thereto; and the indicator reading represents an accurate indication of the value of torque transmitted to the work.

There is interconnected (FIG. 1) intermediately of the passage means- 12 and the throttle valve 10 centrifugally operable air shut-off control mechanism 77 which responds to stalling of the motor to automatically shut off further air flow to the motor. An understanding of the operation of the shut-off control mechanism is not required for the present invention. It is, however, explained in a co-pending US. Pat. application Ser. No. 301,942, filed Oct. 30, 1972.

While an embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not-limited thereto. Various changes can be made in the design and arrangement of the parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art; and it is my intent, therefore, to claim the invention-not only as shown and described hereinbut also in all such forms and modifications as may reasonably be construed to fall within the spirit of the invention and the scope of the appended claims.

What is claimed is: a

l. A nut runner having integral transducer means for transmitting to an external strain gage indicatorelectrical instrument a reaction torque signal, comprising: an air driven torque motor; reduction gear means connected for transmitting torque of the motor to a workpiece; an internal ring gear engaged by and relative'to which the reduction gear means rotates in transmitting the torque of the motor to the work; an elongated reaction torque responsive transducer; a housing containing the motor, gear means, ring gear, and the transducer;

means fixing a forward end of the transducer to a rear end of the ring gear; other means fixing a rear end of the transducer to the housing; a handle attached to the housing in axial extension thereof; an electric cable confined entirely within the housing and the handle; and an electrical outlet plug mounted to the handle adapted for plug connection with the externalstrain gage indicator electrical instrument, the cable being connected at one end with the transducer and connected at its other end with the outlet plug.

2. A nut runner having integral transducer means for transmitting to an external strain gage indicator electrical instrument a reaction torque signal, comprising: an air driven torque motor; reduction gear means connected for transmitting torque of the motor to a workpiece; an internal ring gear engaged by and relative to which the reduction gear means rotates in transmitting the torque of the motor to the work; an elongated reaction torque responsive transducer; a housing containing the motor, gear means, ring gear, and the transducer;

means fixing a forward end of the transducer to a rear end of the ring gear; other means fixing a rear end of the transducer to the housingyand a cable'confined within the housing connected at one end with the rear end of the transducer and adapted at its other end for tion to the drive shaft and having an annular forward head coupled to the ring gear, an annular rear head coupled to the housing, and an elongated intermediate neck in surrounding relation to the drive shaft.

3. A nut runner as in claim 2, wherein the housing includes a linear handle end section; and an electrical plug is coupled to the handle section having a connection with a terminal end of the cable and adapted for electrical connection with the external strain gage indicator electrical instrument.

4. A nut runner as in claim 3, wherein the motor includes a liner fixed with the housing and having a notch in its peripheral surface through which the cable extends from the transducer.

5. A nut runner as in claim 4, wherein the motor has a stall torque air driven vane rotor connected with the drive shaft.

6.'A nut runner as in claim 2, wherein the housing includes an angle head front end; and a drive train within the angle head connects the reduction gear means a work socket adapted for engagement with the workpiece. I a

Patent No. 3,858,+M+ Dated January 7, 1975 William K. Wallace et a1.

Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading, the co-applioant's name and address should be added:

Richard S. Lesner' Madison Heights, Michigan Column 2, line 1LT, "straingage" should be strain gage Column 2, line #7, "nut clamp 1 should be nut clamp 43 Column 6, line 50, with should be inserted after "means".

Signed and sealed this 15th day of [wril 1975.

attest:

c ttgflstrx'f? BEN-7 4I;;.\..'- ill'rflwlr .51.-..2 IQUTZ' C. Commissioner of Patents I'Lttesting Of'icer and Trade'iwrks FORM PC4050 (10-69) USCOMM-DC Bean-P39 4 u.s covzmmzm PRINTING orrncz: 869 93 

1. A nut runner having integral transducer means for transmitting to an external strain gage indicator electrical instrument a reaction torque signal, comprising: an air driven torque motor; reduction gear means connected for transmitting torque of the motor to a workpiece; an internal ring gear engaged by and relative to which the reduction gear means rotates in transmitting the torque of the motor to the work; an elongated reaction torque responsive transducer; a housing containing the motor, gear means, ring gear, and the transducer; means fixing a forward end of the transducer to a rear end of the ring gear; other means fixing a rear end of the transducer to the housing; a handle attached to the housing in axial extension thereof; an electric cable confined entirely within the housing and the handle; and an electrical outlet plug mounted to the handle adapted for plug connection with the external strain gage indicator electrical instrument, the cable being connected at one end with the transducer and connected at its other end with the outlet plug.
 2. A nut runner having integral transducer means for transmitting to an external strain gage indicator electrical instrument a reaction torque signal, comprising: an air driven torque motor; reduction gear means connected for transmitting torque of the motor to a workpiece; an internal ring gear engaged By and relative to which the reduction gear means rotates in transmitting the torque of the motor to the work; an elongated reaction torque responsive transducer; a housing containing the motor, gear means, ring gear, and the transducer; means fixing a forward end of the transducer to a rear end of the ring gear; other means fixing a rear end of the transducer to the housing; and a cable confined within the housing connected at one end with the rear end of the transducer and adapted at its other end for transmitting to the transducer direct current excitation from the external strain gage indicating electrical instrument, wherein an elongated drive shaft connects the motor with the reduction gear means; the transducer is of spool form arranged in coaxial spaced relation to the drive shaft and having an annular forward head coupled to the ring gear, an annular rear head coupled to the housing, and an elongated intermediate neck in surrounding relation to the drive shaft.
 3. A nut runner as in claim 2, wherein the housing includes a linear handle end section; and an electrical plug is coupled to the handle section having a connection with a terminal end of the cable and adapted for electrical connection with the external strain gage indicator electrical instrument.
 4. A nut runner as in claim 3, wherein the motor includes a liner fixed with the housing and having a notch in its peripheral surface through which the cable extends from the transducer.
 5. A nut runner as in claim 4, wherein the motor has a stall torque air driven vane rotor connected with the drive shaft.
 6. A nut runner as in claim 2, wherein the housing includes an angle head front end; and a drive train within the angle head connects the reduction gear means a work socket adapted for engagement with the workpiece. 